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Who knew? The Australian Bureau of Met just made last summer hotter, and history colder (again)

Posted By Jo Nova On October 2, 2019 @ 2:04 am In Global Warming | Comments Disabled

The cheapest way to prevent man-made global warming is stop the BOM altering the data

First the BoM had “high quality” data. Then, with fanfare, after we asked for an audit they had the miracle of ACORN circa 2011. Then early this year ACORN 2.0 was quietly birthed  with major adjustments as expert data became “more expert” but the BOM strangely didn’t want to mention that what was so good is now even better (apparently). The unofficial BOM audit team — especially Bob Fernley-Jones and Chris Gillham — have unearthed just how large the latest rewrite of history is. These men are truly independent, they have no funding, and nothing to gain either way. Please thank them for their unpaid dedication.

In this brazen latest round, even the summer of 2018 just got warmer. After all the headlines, after it was measured on supposedly modern first class equipment, even data just 18 months old is being re-fiddled. The temperatures read out on the news in January 2018? Nevermind what they said then. Those hottest ever records then were even hotter than the BoM thought, thanks to amazing new discoveries that the BOM doesn’t think are important enough to issue as a press release.

This time around the BoM have increased the warming rate by an astonishing 71%.

Who knew? Temperatures in 1910 are still getting colder. Pretty soon we’ll need to send blankets back with Dr Who so our grandparents don’t die of hypothermia.

– Jo


Whopper #1: Bureau of Meteorology covertly (secretly?) made summer hotter

Part 1: Guest post by Bob Fernley-Jones

In 2011, the BoM adjusted Australia’s temperature records with the objective of making corrections for the varying measurement conditions back in time.  Controversially, they deleted all data before 1910 by ruling them unreliable (especially the notably hotter values) and by adjusting the surviving early 1900’s values generally downwards.  Amid the controversy, this program received much official praise and publicity that culminated in a government sponsored report of 2017 declaring it to be among world’s best practice. Despite that acclaim, in October 2018 they found it necessary to quietly launch a new program that further increased warming rates. Whilst there was no media release to inform the public, it was presumably well received by the IPCC.

The two adjustment programs employ a methodology known as homogenization which is described under the acronyms ACORN-SAT (2011), replaced by ACORN-SAT version 2 (hereafter v1 & v2). The discovery of what follows arose from enquiries to the BoM made last year over existing concerns with v1 data and the fortuitous archiving of BoM data and graphics that no longer exist on line (but which are easily proven).   It resulted in citizen researcher awareness of v2 despite the lack of media release and thus in recent interest to compare outcomes.

The first example below animates the changes to the all-Australia summer averages (Southern Hemisphere DJF).  This selection was made to avoid any suggestion of picking the worst case that might otherwise result from regional variability, and it is not the worst case. It is derived from a BoM online download archived in early 2018 compared with the replacing v2 copy and shows a v1 warming rate of 0.07 0C/decade to 2018 and for v2; 0.12 0C/decade to 2019. That results in an increased warming rate of an incredible 71%.

Australian Summer Maxes, animated changes from 2018-2019. Bureau of Meteorology.

Australian Summer Maxes, animated changes from 2018-2019. Bureau of Meteorology.

 Animation by Chris Gillham (waclimate.net)

The extraordinary value in 2019 clearly has an impact on the increased v2 rate but the v1 data were also archived. This has enabled determination of the v2 rate less the 2019 value, as follows:

Australian summer maximums, changes to data 2018 - 2019.

Click to enlarge


From this, the increased warming rate v2 over v1 for 1910 through 2018 is 57% on top of that already accomplished in ‘world’s best practice’ of v1 over the original data.  Typically, cooling adjustments randomly increase downwards towards 1910 and oppositely towards 2019 (the dotted trend lines intersect and pivot roughly in the centre = minimal net adjustments around the centre).

But, it gets worse.  In Part 2, an increase in warming trend of 87% will be revealed, together with another problem where the State average data show inexplicable changes as late as in 2018 when none of its individual stations do (As also with the above but discussed in Part 2).


* Australian Climate Observations Reference Network – Surface Air Temperature (ACORN-SAT) v2

* Technical report defining ACORN-SAT v1 (Trewin 2012)

* Technical report defining ACORN-SAT v2 (Trewin 2018)

* “Bureau’s procedures and data analysis as amongst the best in the world”  (3-year Technical Advisory Forum final report 2017)

*  Online time-series graphics and data v2.

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